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Croton maranonensis: a new species of Euphorbiaceae from the tropical inter-Andean dry valleys
(2024)
We describe Croton maranonensis Riina & Martín-Muñoz sp. nov., a species in Croton section Julocroton (Mart.) G.L.Webster from the seasonally dry tropical forests and shrublands of the inter-Andean valleys. This species is a small shrub occurring along the Marañón river valley in Peru and similar dry areas in southern Ecuador. We surveyed morpho-anatomical characters of the new species and closely related taxa. To confirm the placement of the new species in C. section Julocroton, we conducted a molecular phylogenetic analysis including three accessions of the new species and selected representatives of section Julocroton and related groups within Croton L. Micro- and macro-morphological evidence, and molecular data support C. maranonensis sp. nov. as an independent lineage within the C. section Julocroton clade. We compared the new species with morphologically similar species in the same section that also occur in the Andean region, including C. flavispicatus Rusby, C. triqueter Lam., and C. hondensis (H.Karst.) G.L.Webster.
Highlights
• Northern and eastern grassland-savanna boundary defined by minimum temperature.
• Dynamics of fire, frost and growing season temperatures combine to produce this limit.
• Western limit is related to moisture availability.
• Modern, high-resolution climate data enables refinement of bioclimatic limits.
• Reparameterisation improves global model performance at regional scale.
Abstract
Understanding the controls of biome distributions is crucial for assessing terrestrial ecosystem functioning and its response to climate change. We analysed to what extent differences in climate factors (minimum temperatures, water availability, and growing season temperatures (degree days above 5 °C (GDD5)) might explain the poorly understood borders between grasslands, savannas and shrublands in eastern South Africa. The results were used to improve bioclimatic limits in the dynamic global vegetation model (DGVM) LPJ-GUESS. The vegetation model was also used to explore the role of fire in the biome borders. Results show no clear differences between the adjacent biomes in water availability. Treeless grasslands primarily occur in areas with minimum temperatures and GDD5 values below that of savannas. The standard fire module in LPJ-GUESS is not able to reproduce observed burned area patterns in the study region, but simulations with prescribed fire return intervals show that a combination of low temperatures and fire can explain the treeless state of the grassland biome. These results confirm earlier hypotheses that a combination of low winter temperatures, causing frost damage to trees, and low growing season temperatures that impede tree sapling growth and recruitment, particularly under re-occurring fires, drive the grassland-savanna border. With these insights implemented, the LPJ-GUESS simulation results substantially improved grass distribution in the grassland biome, but challenges remain concerning the grassland-shrubland boundary, tree-grass competition and prognostic fire modelling.
An independent Taiwanese lineage of powdery mildew on the endemic host species Koelreuteria henryi
(2024)
Background: Powdery mildews (Erysiphaceae, Ascomycota) are common plant disease agents and also cause stress for forest and fruit trees worldwide as well as in Taiwan. The powdery mildew Erysiphe bulbouncinula on Koelreuteria host trees was considered an endemic species in China. While in China the host was K. paniculata and only the teleomorph stage found, the anamorph and the teleomorph were both recorded for the host in Taiwan, K. henryi. We aimed to clarify the relationship of the powdery mildews recorded under E. bulbouncinula with an apparently disjunct distribution.
Results: Specimens of powdery mildew on K. henryi from Taiwan were characterized based on the anamorph morphology and DNA sequences. They revealed a new record of Sawadaea koelreuteriae for this host species and Taiwan and a new species of Erysiphe, E. formosana, sister to E. bulbouncinula from China.
Conclusions: In Erysiphe on Koelreuteria hosts, speciation of plant parasitic fungi seems to be correlated with disjunct host and geographic distribution possibly shaped by extinction of potential host species which are known only as fossils. Two of the three extant East Asian species of Koelreuteria are now known as hosts of specific Erysiphe species. We may predict a further not yet discovered Erysiphe species on the third East Asian species, K. bipinnata, in South and Southwest China. In the speciation in Sawadaea, the extinction events in Koelreuteria can be excluded from being involved.
Highlights
• Floating ability facilitates water dispersal.
• Hydrochorous seed dispersal is more effective than wind dispersal.
• Storage in water induced germination rate.
Abstract
In many Central European countries Fraxinus pennsylvanica is an invasive species that spreads rapidly in floodplain forests. The aim of this study was to analyse anemochorous and hydrochorous dispersal distances and to compare the findings with dispersal data for the native Fraxinus excelsior. A simulation revealed that wind dispersal distances are similar for both species, reaching to 120–250 m. By contrast, the mean floating time (50% floating samaras) measured in an experiment was 2 days in the case of F. pennsylvanica and 0.5 days for F. excelsior. This high floating ability facilitates water dispersal over several kilometres in both species, but for the invasive species the modelled mean dispersal distance was 3.7 times higher. A germination test of F. pennsylvanica seeds revealed that the rate, onset and speed of germination increase with the duration of the inundation. After a maximum storage time in water of about 15 days the germination rate amounts to 78%, which was higher than the germination rate of seeds without storage in water (53%). We also found that regeneration was enhanced in flooded areas. Hydrochory, therefore, may be viewed as an important factor explaining the successful invasion of F. pennsylvanica in floodplain forests in Central Europe.
Seed dispersal is hard to measure, and there is still a lack of knowledge about dispersal-related traits of plant species. Therefore, we developed D3, the Dispersal and Diaspore Database (available at
www.seed-dispersal.info), which aims at simplifying ecological and evolutionary analyses by providing and integrating various items related to seed dispersal: empirical studies, functional traits, image analyses and ranking indices (quantifying the adaptation to dispersal modes).
Currently, the database includes data for more than 5000 taxa and 33 items as well as digital images of diaspores (i.e. the dispersal units), seeds, fruits and infructescences. The included items cover common traits like diaspore mass, size, shape, terminal velocity and seed number per diaspore. Furthermore, we present newly or further developed items like ecomorphological categorizations of the diaspore and fruit as well as information from literature on prevailing dispersal modes. Finally, we introduce several items which are not covered in other databases yet: surface structure and form of the diaspore, the exposure of the diaspores in the infructescence and dispersal rankings. Dispersal rankings allow estimations of how well certain species are adapted to a specific dispersal mode in comparison to a larger species set. They are calculated as the percentile rank of an indicator of species’ dispersal potential in relation to a larger species set.
Especially for the new and further developed items we outline the basic concepts in detail, describe the measurement and categorization methods and show how to interpret and integrate these data for single species as well as for larger species sets. Thereby, we calculate baseline statistics of seed dispersal of the Central European flora. We found that diaspores of 72% of the taxa show specializations related to long-distance dispersal, i.e. most often elongated appendages or nutrient-rich tissues. Diaspore masses, sizes and terminal velocities vary over several orders of magnitude and can be approximated by lognormal distributions.
Climate forecasts show that in many regions the temporal distribution of precipitation events will become less predictable. Root traits may play key roles in dealing with changes in precipitation predictability, but their functional plastic responses, including transgenerational processes, are scarcely known. We investigated root trait plasticity of Papaver rhoeas with respect to higher versus lower intra-seasonal and inter-seasonal precipitation predictability (i.e., the degree of temporal autocorrelation among precipitation events) during a four-year outdoor multi-generation experiment. We first tested how the simulated predictability regimes affected intra-generational plasticity of root traits and allocation strategies of the ancestors, and investigated the selective forces acting on them. Second, we exposed three descendant generations to the same predictability regime experienced by their mothers or to a different one. We then investigated whether high inter-generational predictability causes root trait differentiation, whether transgenerational root plasticity existed and whether it was affected by the different predictability treatments. We found that the number of secondary roots, root biomass and root allocation strategies of ancestors were affected by changes in precipitation predictability, in line with intra-generational plasticity. Lower predictability induced a root response, possibly reflecting a fast-acquisitive strategy that increases water absorbance from shallow soil layers. Ancestors’ root traits were generally under selection, and the predictability treatments did neither affect the strength nor the direction of selection. Transgenerational effects were detected in root biomass and root weight ratio (RWR). In presence of lower predictability, descendants significantly reduced RWR compared to ancestors, leading to an increase in performance. This points to a change in root allocation in order to maintain or increase the descendants’ fitness. Moreover, transgenerational plasticity existed in maximum rooting depth and root biomass, and the less predictable treatment promoted the lowest coefficient of variation among descendants’ treatments in five out of six root traits. This shows that the level of maternal predictability determines the variation in the descendants’ responses, and suggests that lower phenotypic plasticity evolves in less predictable environments. Overall, our findings show that roots are functional plastic traits that rapidly respond to differences in precipitation predictability, and that the plasticity and adaptation of root traits may crucially determine how climate change will affect plants.
Phyllanthus novofriburgensis J.C.R.Mendes, J.M.A.Braga & Fraga sp. nov. and P. pedrosae J.C.R.Mendes, J.M.A.Braga & Fraga sp. nov. are new species of Phyllanthaceae described from the Brazilian Atlantic Forest and Brazilian Cerrado, respectively. Phyllanthus novofriburgensis resembles P. acutifolius Poir. ex Spreng., P. hypoleucus Müll.Arg. and P. lilliputianus J.C.R.Mendes, J.M.A.Braga & Fraga, sharing ovate, elliptical, and lanceolate leaf blades. However, it can be distinguished by its pendulous habit, often with sinuous branches and lanceolate leaf blades with characteristically revolute margins. Phyllanthus pedrosae exhibits morphological similarities with P. claussenii Müll.Arg. due to its subshrubby and prostrate habit. It is distinghuished by the unisexual inflorescence with cymules composed of one or two staminate flowers proximally positioned in the axil of the branches and solitary pistillate flowers distally situated, and the 5-merous calyx in the staminate and pistillate flowers. Both new species are classified in Phyllanthus subgen. Phyllanthus sect. Phyllanthus subsect. Clausseniani G.L.Webster, primarily due to the deeply emarginate anthers. Notes on their geographical distribution and habitat are provided, as well as a key to the species of Phyllanthus from Southeastern Brazil.
The fossil record of the diverse subfamily Passifloroideae (>750 species and 17 genera) is relatively poor. Despite the distinctiveness of its leaves (glandular and often emarginate), most of the fossils from this group have been described from seeds. Fossil seeds have been recovered from Europe, and North and South America. A lack of information on seed morphology for all the genera and tribes of this subfamily has prevented a tribe-level identification of the fossils and a better understanding of their biogeographic patterns. The Passifloroideae is divided into three tribes: Passifloreae with 10 genera, Paropsieae with six genera and the monotypic Jongkindieae. This study provides new descriptions for 15 species from 5 genera from the mostly Afrotropical tribe Paropsieae based on herbarium material, and introduces an online seed database and a key for 100 species of Passifloroideae compiled from literature and direct observations. Our study shows a low morphological diversity among the seeds of Paropsieae in comparison to a much larger diversity within Passifloreae. Some rare morphologies are only present in Passifloreae and can be used to assign seeds to this tribe. Within the Paropsieae, Androsiphonia has seed that are very distinct from those in the other genera in the tribe and also from the rest of the subfamily. The genus Paropsia exhibits two main morphotypes, while the genera Barteria, Paropsiopsis and Smeathmannia have very similar seeds with a highly conserved morphology. These results suggest that living or fossil Paropsieae cannot be identified confidently based solely on seed characters.
Forest wildflowers bloom earlier as Europe warms: lessons from herbaria and spatial modelling
(2022)
Today plants often flower earlier due to climate warming. Herbarium specimens are excellent witnesses of such long-term changes. However, the magnitude of phenological shifts may vary geographically, and the data are often clustered. Therefore, large-scale analyses of herbarium data are prone to pseudoreplication and geographical biases.
We studied over 6000 herbarium specimens of 20 spring-flowering forest understory herbs from Europe to understand how their phenology had changed during the last century. We estimated phenology trends with or without taking spatial autocorrelation into account.
On average plants now flowered over 6 d earlier than at the beginning of the last century. These changes were strongly associated with warmer spring temperatures. Flowering time advanced 3.6 d per 1°C warming. Spatial modelling showed that, in some parts of Europe, plants flowered earlier or later than expected. Without accounting for this, the estimates of phenological shifts were biased and model fits were poor.
Our study indicates that forest wildflowers in Europe strongly advanced their phenology in response to climate change. However, these phenological shifts differ geographically. This shows that it is crucial to combine the analysis of herbarium data with spatial modelling when testing for long-term phenology trends across large spatial scales.
Field work in the Kibira National Park (Burundi), located in the Kivu-Ruwenzori system of the Afromontane Region, revealed the existence of a new species clearly belonging to the Argocoffeopsis-Calycosiphonia clade (Coffeeae, Rubiaceae). The species shows striking heterophylly: the plagiotropous branches have several nodes bearing reduced or even scaly leaves. For the rest, it shares characters with Calycosiphonia and Kupeantha. Therefore, a morphological comparison with the clade is done, as well as molecular phylogenetic analyses. The morphology of the novelty is closer to Kupeantha than to Calycosiphonia, inter alia because the anthers have no transverse septa, in contrast to the multilocellate anthers of Calycosiphonia. However, the molecular data advocate for a position in Calycosiphonia – a result weakening the morphological distinction between Calycosiphonia and Kupeantha. The former genus is no longer restricted to species with transverse septa in the anthers and with placental outgrowths around the seed. The new species is formally described as Calycosiphonia albertina Ntore & Robbr. sp. nov. Nomenclaturally, this placement is also the most conservative option. A taxonomic treatment, illustrations, a geographical distribution map, and a preliminary conservation assessment are provided. The previous inclusion of Calycosiphonia pentamera in Kupeantha based on morphology is here corroborated by molecular analyses.
Diospyros L. is a large genus of flowering plants predominantly distributed in the tropics. It comprises over 700 species globally and around 300 are believed to occur in South-East Asia. Many species are economically important and exploited for the production of ebony wood and persimmons, yet taxonomic information on the genus is incomplete and inconsistent due to its morphological and nomenclatural complexity. Revisions of Diospyros in continental and insular South-East Asia were conducted independently by different authors, occasionally with different names used for the same species, or different species being given the same name in different countries. During our ongoing study of the genus Diospyros in Indochina (Cambodia, Laos, Thailand and Vietnam), we identified several such instances. Here, we clarify the most commonly misidentified species, including 1) D. apiculata Hiern, D. strigosa Hemsl. and D. tamiriensis Lecomte; 2) D. bejaudii Lecomte and D. retrofracta Bakh.; 3) D. dictyoneura Hiern and D. hasseltii Zoll.; 4) D. borneensis Hiern and D. fecunda H.R.Fletcher. Lectotypifications are also made for D. brachiata King & Gamble var. lanceolata H.R.Fletcher, D. fecunda, D. similis Craib and D. strigosa.
Abstract
Natural plant populations often harbour substantial heritable variation in DNA methylation. However, a thorough understanding of the genetic and environmental drivers of this epigenetic variation requires large-scale and high-resolution data, which currently exist only for a few model species. Here, we studied 207 lines of the annual weed Thlaspi arvense (field pennycress), collected across a large latitudinal gradient in Europe and propagated in a common environment. By screening for variation in DNA sequence and DNA methylation using whole-genome (bisulfite) sequencing, we found significant epigenetic population structure across Europe. Average levels of DNA methylation were strongly context-dependent, with highest DNA methylation in CG context, particularly in transposable elements and in intergenic regions. Residual DNA methylation variation within all contexts was associated with genetic variants, which often co-localized with annotated methylation machinery genes but also with new candidates. Variation in DNA methylation was also significantly associated with climate of origin, with methylation levels being lower in colder regions and in more variable climates. Finally, we used variance decomposition to assess genetic versus environmental associations with differentially methylated regions (DMRs). We found that while genetic variation was generally the strongest predictor of DMRs, the strength of environmental associations increased from CG to CHG and CHH, with climate-of-origin as the strongest predictor in about one third of the CHH DMRs. In summary, our data show that natural epigenetic variation in Thlaspi arvense is significantly associated with both DNA sequence and environment of origin, and that the relative importance of the two factors strongly depends on the sequence context of DNA methylation. T. arvense is an emerging biofuel and winter cover crop; our results may hence be relevant for breeding efforts and agricultural practices in the context of rapidly changing environmental conditions.
Author summary
Variation within species is an important level of biodiversity, and it is key for future adaptation. Besides variation in DNA sequence, plants also harbour heritable variation in DNA methylation, and we want to understand the evolutionary significance of this epigenetic variation, in particular how much of it is under genetic control, and how much is associated with the environment. We addressed these questions in a high-resolution molecular analysis of 207 lines of the common plant field pennycress (Thlaspi arvense), which we collected across Europe, propagated under standardized conditions, and sequenced for their genetic and epigenetic variation. We found large geographic variation in DNA methylation, associated with both DNA sequence and climate of origin. Genetic variation was generally the stronger predictor of DNA methylation variation, but the strength of environmental association varied between different sequence contexts. Climate-of-origin was the strongest predictor in about one third of the differentially methylated regions in the CHH context, which suggests that epigenetic variation may play a role in the short-term climate adaptation of pennycress. As pennycress is currently being domesticated as a new biofuel and winter cover crop, our results may be relevant also for agriculture, particularly in changing environments.
Abstract
Natural plant populations often harbour substantial heritable variation in DNA methylation. However, a thorough understanding of the genetic and environmental drivers of this epigenetic variation requires large-scale and high-resolution data, which currently exist only for a few model species. Here, we studied 207 lines of the annual weed Thlaspi arvense (field pennycress), collected across a large latitudinal gradient in Europe and propagated in a common environment. By screening for variation in DNA sequence and DNA methylation using whole-genome (bisulfite) sequencing, we found significant epigenetic population structure across Europe. Average levels of DNA methylation were strongly context-dependent, with highest DNA methylation in CG context, particularly in transposable elements and in intergenic regions. Residual DNA methylation variation within all contexts was associated with genetic variants, which often co-localized with annotated methylation machinery genes but also with new candidates. Variation in DNA methylation was also significantly associated with climate of origin, with methylation levels being higher in warmer regions and lower in more variable climates. Finally, we used variance decomposition to assess genetic versus environmental associations with differentially methylation regions (DMRs). We found that while genetic variation was generally the strongest predictor of DMRs, the strength of environmental associations increased from CG to CHG and CHH, with climate-of-origin as the strongest predictor in about one third of the CHH DMRs. In summary, our data show that natural epigenetic variation in Thlaspi arvense is significantly associated with both DNA sequence and environment of origin, and that the relative importance of the two factors strongly depends on the sequence context of DNA methylation. T. arvense is an emerging biofuel and winter cover crop; our results may hence be relevant for breeding efforts and agricultural practices in the context of rapidly changing environmental conditions.
Author Summary: Variation within species is an important level of biodiversity, and it is key for future adaptation. Besides variation in DNA sequence, plants also harbour heritable variation in DNA methylation, and we want to understand the evolutionary significance of this epigenetic variation, in particular how much of it is under genetic control, and how much is associated with the environment. We addressed these questions in a high-resolution molecular analysis of 207 lines of the common plant field pennycress (Thlaspi arvense), which we collected across Europe, propagated under standardized conditions, and sequenced for their genetic and epigenetic variation. We found large geographic variation in DNA methylation, associated with both DNA sequence and climate of origin. Genetic variation was generally the stronger predictor of DNA methylation variation, but the strength of environmental association varied between different sequence contexts. Climate-of-origin was the strongest predictor in about one third of the differentially methylated regions in the CHH context, which suggests that epigenetic variation may play a role in the short-term climate adaptation of pennycress. As pennycress is currently being domesticated as a new biofuel and winter cover crop, our results may be relevant also for agriculture, particularly in changing environments.
Tilletia caries and T. laevis, which are the causal agents of common bunt, as well as T. controversa, which causes dwarf bunt of wheat, threaten especially organic wheat farming. The three closely related fungal species differ in their teliospore morphology and partially in their physiology and infection biology. The gene content as well as intraspecies variation in these species and the genetic basis of their separation is unknown. We sequenced the genome of four T. caries, five T. controversa, and two T. laevis and extended this dataset with five publicly available ones. The genomes of the three species displayed microsynteny with up to 94.3% pairwise aligned regions excluding repetitive regions. The majority of functionally characterized genes involved in pathogenicity, life cycle, and infection of corn smut, Ustilago maydis, were found to be absent or poorly conserved in the draft genomes and the biosynthetic pathway for trimethylamine in Tilletia spp. could be different from bacteria. Overall, 75% of the identified protein-coding genes comprising 84% of the total predicted carbohydrate utilizing enzymes, 72.5% putatively secreted proteins, and 47.4% of effector-like proteins were conserved and shared across all 16 isolates. We predicted nine highly identical secondary metabolite biosynthesis gene clusters comprising in total 62 genes in all species and none were species-specific. Less than 0.1% of the protein-coding genes were species-specific and their function remained mostly unknown. Tilletia controversa had the highest intraspecies genetic variation, followed by T. caries and the lowest in T. laevis. Although the genomes of the three species are very similar, employing 241 single copy genes T. controversa was phylogenetically distinct from T. caries and T. laevis, however these two could not be resolved as individual monophyletic groups. This was in line with the genome-wide number of single nucleotide polymorphisms and small insertions and deletions. Despite the conspicuously different teliospore ornamentation of T. caries and T. laevis, a high degree of genomic identity and scarcity of species-specific genes indicate that the two species could be conspecific.
Due to massive energetic investments in woody support structures, trees are subject to unique physiological, mechanical, and ecological pressures not experienced by herbaceous plants. Despite a wealth of studies exploring trait relationships across the entire plant kingdom, the dominant traits underpinning these unique aspects of tree form and function remain unclear. Here, by considering 18 functional traits, encompassing leaf, seed, bark, wood, crown, and root characteristics, we quantify the multidimensional relationships in tree trait expression. We find that nearly half of trait variation is captured by two axes: one reflecting leaf economics, the other reflecting tree size and competition for light. Yet these orthogonal axes reveal strong environmental convergence, exhibiting correlated responses to temperature, moisture, and elevation. By subsequently exploring multidimensional trait relationships, we show that the full dimensionality of trait space is captured by eight distinct clusters, each reflecting a unique aspect of tree form and function. Collectively, this work identifies a core set of traits needed to quantify global patterns in functional biodiversity, and it contributes to our fundamental understanding of the functioning of forests worldwide.
Seed dispersal is a key ecosystem function for plant regeneration, as it involves the movement of seeds away from the parental plants to particular habitats where they can germinate and transition to seedlings and ultimately adult plants. Seed dispersal is shaped by a diversity of abiotic and biotic factors, particularly by associations between plants and climate and between plants and other species. Due to the ongoing loss of biodiversity and changing global conditions, such interactions are prone to change and pose a severe threat to plant regeneration. One way to address this challenge is to study associations between plant traits and abiotic and biotic factors to understand the potential impacts of global change on plant regeneration. Plant communities have long been analyzed through the lens of vegetative traits, mainly ignoring how other traits interact and respond to the environment. For instance, while associations between vegetative traits (e.g., specific leaf area, leaf nitrogen content) and climate are well studied, there are few case studies of reproductive traits in relation to trait-environment associations in the context of global change.
Thus, the overarching aim of this dissertation is to explore how trait-environment associations, with a special focus on reproductive traits, can improve our understanding of the effect that global change may have on seed dispersal, and ultimately on plant regeneration. To this end, my research focuses on studying associations between plant traits and abiotic and biotic factors along an elevational gradient in both forests and deforested areas of tropical mountains. This dissertation addresses three principal research objectives.
First, I investigate the extent to which reproductive (seed and fruit traits) and vegetative traits (leaf traits) are related to abiotic and biotic factors for communities of fleshy-fruited plants in the Ecuadorian Andes. I used multivariate analyses to test associations between four (a)biotic factors and seven reproductive traits and five vegetative traits measured on 18 and 33 fleshy fruited plant species respectively. My analyses demonstrate that climate and soil conditions are strongly associated with the distribution of both reproductive and vegetative traits in tropical tree communities. The production of “costly” vs. “cheap” seeds, fruits and leaves, i.e., the production of few rewarding fruits and acquisitive leaves versus the production of many less-rewarding fruits and conservative leaves, is primarily limited by temperature, whereas the size of plant organs is more related to variation in precipitation and soil conditions. My findings suggest that associations between reproductive and vegetative traits and the abiotic environment follow similar principles in tropical tree communities.
Second, I assess how climate and microhabitat conditions affect the prevalence of endozoochorous plant species in the seed rain of tropical montane forests in southern Ecuador. I analyzed seed rain data for an entire year from 162 traps located across an elevational gradient spanning of 2000 m. I documented the microhabitat conditions (leaf area index and soil moisture next to each seed trap) at small spatial scale as well as the climatic conditions (mean annual temperature and rainfall in each plot) at large spatial scale. After a one-year of sampling, I counted 331,838 seeds of 323 species/morphospecies. My analyses demonstrate that the prevalence of endozoochorous plant species in the seed rain increases with temperature across elevations and with leaf area index within elevations. These results show that the prevalence of endozoochory is shaped by the interplay of both abiotic and biotic factors at large and small spatial scales.
Third, I examine the potential of seed rain to restore deforested tropical areas along an elevational gradient in southern Ecuador. For this chapter, I collected seed rain using 324 seed traps installed in 18 1-ha plots in forests (nine forest plots) and in pastures (nine deforested plots) along an elevational gradient of 2000 m. After a sampling period of three months, I collected a total of 123,039 seeds of 255 species/morphospecies from both forests and pastures along the elevational gradient. I did not find a consistent decrease in the amount and richness of seed rain between forests and pastures, but I detected a systematic change in the type of dispersed seeds, as heavier seeds and a higher proportion of endozoochorous species were found in forests compared to pastures at all elevations. This finding suggests that deforestation acts as a strong filter selecting seed traits that are vital for plant regeneration.
Understanding the role that trait-environment associations play in how plant communities regenerate today could serve as a basis for predicting changes in regeneration processes of plant communities under changing global conditions in the near future. Here, I show how informative the measurement of reproductive traits and trait environment associations are in facilitating the conservation of forest habitats and the restoration of deforested areas in the context of global change.
The lianescent genus Tinospora Miers in Singapore is revised. Four species are recognised, two of which are newly described. Tinospora krispura I.M.Turner sp. nov. is known from Christmas Island and Singapore. Tinospora singapura I.M.Turner sp. nov. is known only from Singapore. Two new lectotypifications are included, one at the second step.
Around 400 BC, pottery- and iron-producing populations immigrated into the Inner Congo Basin (ICB) and subsequently spread upstream some major tributaries of the Congo River. Until recently, their subsistence was almost completely unknown. We present an archaeobotanical study of three sites in the ICB covering parts of the Early Iron Age (ca. 400 BC-AD 650) and of the Late Iron Age (LIA) as well as subrecent times (ca. AD 1300–2000). We studied 82 flotated samples of botanical macroremains, and 68 soil phytolith samples, recovered from the terra firme sites Iyonda and Mbandaka, and the floodplain fishing camp site of Bolondo. The EIA assemblage from Iyonda yielded domesticated Cenchrus americanus (pearl millet), Vigna unguiculata (cowpea), Canarium schweinfurthii, Elaeis guineensis (oil palm), several wild plants, and parenchyma fragments tentatively attributed to Dioscorea sp. (yams). The exploitation of these plants originated in the savannas and forest-savanna ecotones of West Africa. The presence of C. americanus in LIA contexts at Bolondo and Mbandaka, dated to ca. AD 1350–1550, indicates that its cultivation is not dependent on a seasonal climate with a distinct dry season, contrary to previous views. The role of C. americanus as a staple is difficult to assess; it might have been used for special purposes, e.g. beer brewing. In spite of extensive screening, we did not detect any banana phytoliths in the EIA samples. Musa phytoliths were only present in LIA contexts after ca. AD 1400, leaving room for the possibility that the introduction and spread of Musa spp. AAB ‘Plantain’ in the ICB was a late phenomenon.
A comprehensive checklist of Habenaria from Chapada dos Veadeiros, State of Goiás, was performed alongside morphologic and molecular phylogenetic studies, revealing three new taxa endemic to this region. A total of 61 taxa (59 species and two varieties) of Habenaria are recorded for Chapada dos Veadeiros, representing a two-fold increase compared to previous lists and comprising one of the greatest diversities of the genus in Brazil. Of this total, four taxa are locally endemic. Habenaria cultellifolia, until recently known only from the type collection, was rediscovered in the region after 127 years without records and represents this species’ only known extant population. Three proposed new taxa of Habenaria (H. minuticalcar J.A.N. Bat. & Bianch. sp. nov., H. proiteana J.A.N. Bat., A.A. Vale & Bianch. sp. nov., and H. lavrensis var. xanthodactyla J.A.N. Bat. & Bianch. var. nov.) are corroborated by molecular phylogenetic analyses based on nuclear and plastid markers. They are described, illustrated, tentatively assessed as threatened, and compared to phylogenetically and morphologically related species. Since some areas of this mountain range have not yet been floristically sampled, additional taxonomic novelties and new records are still expected in the future.
Questions: Both species turnover and intraspecific trait variation can affect plant assemblage dynamics along environmental gradients. Here, we asked how community assemblage patterns in relation to species turnover and intraspecific variation differ between endemic and non-endemic species. We hypothesized that endemic species show lower intraspecific variation than non-endemic species because they tend to have high rates of in situ speciation, whereas non-endemic species are expected to have a larger gene pool and higher phenotypic plasticity.
Location: La Palma, Canary Islands.
Methods: We established 44 sampling sites along a directional gradient of precipitation, heat load, soil nitrogen, phosphorus and pH. Along this gradient, we estimated species abundances and measured three traits (plant height, leaf area and leaf thickness) on perennial endemic and non-endemic plant species. In total, we recorded traits for 1,223 plant individuals of 43 species. Subsequently, we calculated community-weighted mean traits to measure the relative contribution of species turnover, intraspecific variation and their covariation along the analysed gradient.
Results: The contribution of intraspecific variation to total variation was similar in endemic and non-endemic assemblages. For plant height, intraspecific variation explained roughly as much variation as species turnover. For leaf area and leaf thickness, intraspecific variation explained almost no variation. Species turnover effects mainly drove trait responses along the environmental gradient, but intraspecific variation was important for responses in leaf area to precipitation.
Conclusions: Despite their distinct evolutionary history, endemic and non-endemic plant assemblages show similar patterns in species turnover and intraspecific variation. Our results indicate that species turnover is the main component of trait variation in the underlying study system. However, intraspecific variation can increase individual species’ fitness in response to precipitation. Overall, our study challenges the theory that intraspecific trait variation is more important for the establishment of non-endemic species compared with endemic species.
Differential derepression of the genome of potato tuber cells can be initiated by slicing the tissue into disks. The consequence of this procedure on the cells of the wound surface is dedifferentiation and cell division followed by redifferentiation to a suberized phellem cell. The drift of glucose-, glucose-1-phosphate-, glucose-6-phosphate-, fructose-6-phosphate- and 6-phospho-gluconatelevels has been determined in the derepressed tissue. With the exception of 6-phospho-gluconate all intermediates so far investigated showed a rise in concentration after derepression.
This is interpreted as a consequence of altered enzymic activities which were estimated for phosphoglucomutase, hexokinase, phosphoglucoisomerase, gluco-6-phosphate- and 6-phosphogluconatedehydrogenase. The two dehydrogenases were activated after derepression, the activation represented a de-novo-synthesis, as was demonstrated with the inhibitors Actidione (translation) and p-Fluorophenyl-alanine (protein synthesis in general). Hexokinase and phosphoglucoisomerase were not severely affected by cutting the tissue. Phosphoglucomutase was degrated rapidly, the degradation being dependent on protein synthesis. The importance of an enhanced activity of the pentose phosphate shunt for the stressed cell is emphasized and the possibility of an alteration in the osmotic pressure within the cell and especially in the nucleus — a primary consequence of wounding — as a cause of derepression in potato tuber cells is discussed.
Positive plant–plant interactions are thought to drive vegetation patterns in harsh environments, such as semi-arid areas. According to the stress-gradient hypothesis (SGH), the role of positive interactions between species (facilitation) is expected to increase with harshness, predicting associated variation in species composition along environmental gradients. However, the relation between stress and facilitation along environmental gradients is debated. Furthermore, differentiating facilitative interactions from other underlying mechanisms, such as microtopographic heterogeneity, is not trivial. We analysed the spatial co-occurrence relationships of vascular plant species that form patchy vegetation in arid lapilli fields (tephra) from recent volcanic eruptions on La Palma, Canary Islands. Assuming a harshness gradient negatively correlated with elevation because the lower elevations are more arid and water availability is considered the most limiting resource, and that an outcome of facilitation is plants co-occurring in the same patch, from the SGH we expected a greater degree of co-occurrence at lower elevation. We tested this at both the species and the individual plant level. We analysed the species composition of 1277 shrubby vegetation patches at 64 different sampling points, ranging from the coast to around 700 m a.s.l. Patch morphology and microtopographic heterogeneity variables were also measured, to account for their potential effects on the species composition of patches. We used generalized linear models and generalized mixed-effects models to analyse species richness, number of individuals in patches and percentage of patches with positive co-occurrences, and a pairwise co-occurrence analysis combined with a graphical network analysis to reveal positive links between 13 of the species. We found that the percentage of patches with positive co-occurrences increased at higher elevations, in contrast to the predictions of the SGH, but in accordance with a refined stress-gradient hypothesis for arid sites, in which characteristics of the interacting species are incorporated.
We present a preliminary discussion about cauliflory, sexual dimorphism and biogeographic patterns in Drypetes Vahl (Putranjivaceae Endl.), focused on Africa. We also present a taxonomic treatment for two new species of cauliflorous trees of this genus from the rainforests of western Central Africa, one endemic to Gabon and known from six gatherings, D. aphanes Quintanar, D.J.Harris & Barberá sp. nov., and the other distributed in Gabon and the Republic of the Congo, D. cauta D.J.Harris, Barberá & Quintanar sp. nov., also known from another six gatherings. They are presented along with D. gabonensis Pierre ex Hutch., known from 25 gatherings made throughout western Central Africa, a species with markedly dimorphic flowers between sexes compared to the rest of the species in the genus. Specimens of these two new species have been confused with D. gabonensis due to some morphological resemblances. This treatment includes the detailed descriptions of these three species, the typification of their names, a comparative table summarizing their main morphological differences, an identification key, an illustration and information about their habitat and distribution. A provisional IUCN Red List assessment shows that D. gabonensis and D. cauta sp. nov. are ‘Vulnerable’ species, and D. aphanes sp. nov. is ‘Endangered’. After the publication of these new species, Drypetes consists of 86 species in continental Africa and the Malagasy Region and 219 species for the whole world.
Merianthera is a genus of flowering plants with up to now seven species occurring in eastern Brazil, in the states of Bahia, Espírito Santo, and Minas Gerais. It belongs to the tribe Pyramieae (Melastomataceae), and can be recognized by its shrubby or treelet habit with caducous leaves, 5-merous flowers with a strongly zygomorphic androecium, the latter with dimorphic stamens bearing complex dorsal connective appendages, as well as an inferior ovary and capsular fruits. We describe here a new species of Merianthera from two collections and a photographic record, all from the same locality, an inselberg in the Municipality of Jacinto, in northeastern Minas Gerais. Its candelabriform habit, with a fistulose stem, and solitary, axillary or cauliflorous flowers are only shared with M. burlemarxii. However, M. calyptrata R.Goldenb., Bochorny & Fraga sp. nov. has at least three characters that are absent in M. burlemarxii and all other species in the genus: the total absence of both a peduncle and bracteoles, the calyptrate calyx and the fruits developing from inferior ovaries and dehiscing through longitudinal slits. The first character appears to be unknown in other species in the family.
The European Beech is the dominant climax tree in most regions of Central Europe and valued for its ecological versatility and hardwood timber. Even though a draft genome has been published recently, higher resolution is required for studying aspects of genome architecture and recombination. Here we present a chromosome-level assembly of the more than 300 year-old reference individual, Bhaga, from the Kellerwald-Edersee National Park (Germany). Its nuclear genome of 541 Mb was resolved into 12 chromosomes varying in length between 28 Mb and 73 Mb. Multiple nuclear insertions of parts of the chloroplast genome were observed, with one region on chromosome 11 spanning more than 2 Mb of the genome in which fragments up to 54,784 bp long and covering the whole chloroplast genome were inserted randomly. Unlike in Arabidopsis thaliana, ribosomal cistrons are present in Fagus sylvatica only in four major regions, in line with FISH studies. On most assembled chromosomes, telomeric repeats were found at both ends, while centromeric repeats were found to be scattered throughout the genome apart from their main occurrence per chromosome. The genome- wide distribution of SNPs was evaluated using a second individual from Jamy Nature Reserve (Poland). SNPs, repeat elements and duplicated genes were unevenly distributed in the genomes, with one major anomaly on chromosome 4. The genome presented here adds to the available highly resolved plant genomes and we hope it will serve as a valuable basis for future research on genome architecture and for understanding the past and future of European Beech populations in a changing climate.
We provide a floristic account for the Begoniaceae of Peru. The family is represented in Peru by 76 species, which are all members of the genus Begonia and represent eighteen sections. Twelve new species are described: B. condorensis Jara & Moonlight sp. nov., B. deltoides Moonlight sp. nov., B. huancabambae Moonlight sp. nov., B. imbrexiformis Moonlight sp. nov., B. longinqua Moonlight sp. nov., B. longitepala Moonlight sp. nov., B. nunezii Moonlight sp. nov., B. occultata J.P.Allen & Moonlight sp. nov., B. pedemontana Moonlight sp. nov., B. serratistipula Moonlight sp. nov., B. vargasii Moonlight sp. nov. and B. yuracyacuensis Moonlight sp. nov. We also provide four new records for the country: B. andina Rusby, B. brandbygeana L.B.Sm. & Wassh., B. neoharlingii L.B.Sm. & Wassh. and B. unilateralis Rusby. We provide an identification key to all species. The ecology, distribution, and conservation status of all Peruvian Begonia species are discussed, including provisional IUCN threat assessments. Most species are illustrated by either historical illustrations, contemporary photographic plates, or line drawings. Twenty-six names are newly synonymised including fifteen previously accepted species, and we designate eighty-three lectotypes, four neotypes, and four epitypes.
The change in allele frequencies within a population over time represents a fundamental process of evolution. By monitoring allele frequencies, we can analyze the effects of natural selection and genetic drift on populations. To efficiently track time-resolved genetic change, large experimental or wild populations can be sequenced as pools of individuals sampled over time using high-throughput genome sequencing (called the Evolve & Resequence approach, E&R). Here, we present a set of experiments using hundreds of natural genotypes of the model plant Arabidopsis thaliana to showcase the power of this approach to study rapid evolution at large scale. First, we validate that sequencing DNA directly extracted from pools of flowers from multiple plants -- organs that are relatively consistent in size and easy to sample -- produces comparable results to other, more expensive state-of-the-art approaches such as sampling and sequencing of individual leaves. Sequencing pools of flowers from 25-50 individuals at ∼40X coverage recovers genome-wide frequencies in diverse populations with accuracy r > 0.95. Secondly, to enable analyses of evolutionary adaptation using E&R approaches of plants in highly replicated environments, we provide open source tools that streamline sequencing data curation and calculate various population genetic statistics two orders of magnitude faster than current software. To directly demonstrate the usefulness of our method, we conducted a two-year outdoor evolution experiment with A. thaliana to show signals of rapid evolution in multiple genomic regions. We demonstrate how these laboratory and computational Pool-seq-based methods can be scaled to study hundreds of populations across many climates.
In search for practical silvicultural management tools to identify alternative tree species for predicted Central European climate conditions, a cross-species survey with five evergreen, semi-evergreen, and deciduous Quercus taxa with contrasting morphological leaf traits was performed. Fast chlorophyll fluorescence induction of PSII and relative leaf chlorophyll contents were performed to assess the overall plant vitality at any point in time during two complete vegetation periods in consecutive years (2012 and 2013). Maximum photochemical efficiency of PSII and the performance index on absorption base showed a very conservative relationship to each other and a similar intra-annual progress in all deciduous species, but with a different speed of increase and decrease during leaf development and senescence and thus a different length of vegetation period. The intra-annual variability of OJIP and chlorophyll content parameters is considered with respect to the practicability of measurements in the field for management purposes.
The European Beech is the dominant climax tree in most regions of Central Europe and valued for its ecological versatility and hardwood timber. Even though a draft genome has been published recently, higher resolution is required for studying aspects of genome architecture and recombination. Here, we present a chromosome-level assembly of the more than 300 year-old reference individual, Bhaga, from the Kellerwald-Edersee National Park (Germany). Its nuclear genome of 541 Mb was resolved into 12 chromosomes varying in length between 28 and 73 Mb. Multiple nuclear insertions of parts of the chloroplast genome were observed, with one region on chromosome 11 spanning more than 2 Mb which fragments up to 54,784 bp long and covering the whole chloroplast genome were inserted randomly. Unlike in Arabidopsis thaliana, ribosomal cistrons are present in Fagus sylvatica only in four major regions, in line with FISH studies. On most assembled chromosomes, telomeric repeats were found at both ends, while centromeric repeats were found to be scattered throughout the genome apart from their main occurrence per chromosome. The genome-wide distribution of SNPs was evaluated using a second individual from Jamy Nature Reserve (Poland). SNPs, repeat elements and duplicated genes were unevenly distributed in the genomes, with one major anomaly on chromosome 4. The genome presented here adds to the available highly resolved plant genomes and we hope it will serve as a valuable basis for future research on genome architecture and for understanding the past and future of European Beech populations in a changing climate.
Die Genetik hat die Landwirtschaft erheblich vorangebracht, weil sich mit ihrer Hilfe wesentlich ertragreichere Arten züchten lassen. Dabei werden Pflanzen mit vorteilhaften Eigenschaften ausgewählt und mit solchen gekreuzt, die andere erstrebenswerte Merkmale aufweisen. Auf diese Weise erhält man hybride Pflanzensorten, die beispielsweise widerstandsfähiger gegenüber Schädlingen und Krankheiten sind und sich besser an unterschiedliche Umweltbedingungen anpassen können. Aber das reicht nicht mehr, selbst mit den leistungsfähigsten und ertragreichsten Zuchtpflanzen steht die Landwirtschaft vor großen Herausforderungen: Klimawandel, Wasserknappheit und schlechte Bodenqualität begrenzen die Höhe landwirtschaftlicher Erträge, gleichzeitig wächst mit der Weltbevölkerung natürlich auch der Bedarf an Nahrungsmitteln. Wesentliche Fortschritte in der Nahrungsmittelerzeugung sind allerdings zu erwarten, wenn bei der Entwicklung von Nahrung nicht nur genetische, sondern auch epigenetische Verfahren angewandt werden, um Nahrungspflanzen weiterzuentwickeln – Verfahren, die darauf beruhen, einzelne Gene gezielt an- und abzuschalten. Seit einigen Jahren forscht dazu an der Goethe-Universität der Molekularbiologe Dr. Sotirios Fragkostefanakis.
In the course of global climate change, central Europe is experiencing more frequent and prolonged periods of drought. The drought years 2018 and 2019 affected European beeches (Fagus sylvatica L.) differently: even in the same stand, drought damaged trees neighboured healthy trees, suggesting that the genotype rather than the environment was responsible for this conspicuous pattern. We used this natural experiment to study the genomic basis of drought resistance with Pool-GWAS. Contrasting the extreme phenotypes identified 106 significantly associated SNPs throughout the genome. Most annotated genes with associated SNPs (>70%) were previously implicated in the drought reaction of plants. Non-synonymous substitutions led either to a functional amino acid exchange or premature termination. A SNP-assay with 70 loci allowed predicting drought phenotype in 98.6% of a validation sample of 92 trees. Drought resistance in European beech is a moderately polygenic trait that should respond well to natural selection, selective management, and breeding.
Buchbesprechungen
(2023)
Campanula cervicaria steht in Hessen kurz vor dem Aussterben und wurde im Rahmen des Kooperationsvertrages zwischen der Botanischen Vereinigung für Naturschutz in Hessen (BVNH) und dem Land Hessen untersucht. Das Ziel der Untersuchung war, herauszufinden wo Campanula cervicaria in Hessen noch vorkommt und wie groß die Populationen sind. In Hessen sind aktuell noch 20 Populationen vorhanden. Fast 90 % der Populationen befinden sich in der Umgebung von Lißberg, Hirzenhain und Gedern im Westlichen Unteren Vogelsberg. Zwei weitere liegen bei Jossa im Spessart und bei Ober-Gleen im Nördlichen Vogelsberg-Vorland. Die größte Population befindet sich an der Kreisstraße 216 bei Hirzenhain am Forsthaus Luisenlust. Campanula cervicaria wächst in Hessen an sonnenexponierten Wegböschungen und Windwurfflächen, meist zusammen mit Hypericum hirsutum und Brachypodium sylvaticum. Um auch zukünftig die Bestände von Campanula cervicaria zu sichern, müsste ein Artenhilfskonzept erarbeitet werden.
Betrachtet man die Anzahl der in Hessen ausgestorbenen Pflanzenarten über den gesamten Zeitraum ab Beginn der floristischen Erforschung, so scheint ein Zusammenhang zwischen der geringeren Anzahl ausgestorbener Arten in den letzten Dekaden und den gleichzeitig vermehrt ausgewiesenen Naturschutzgebieten zu bestehen. Es stellt sich daher die Frage, ob es auch einen kausalen Zusammenhang gibt, oder ob andere Faktoren einen Einfluss auf das Ausmaß an ausgestorbenen Pflanzenarten haben. Für die Entwicklung der Aussterberate in den kommenden Jahrzehnten wird es nötig werden, alle Vorkommen der derzeit vom Aussterben bedrohten Pflanzenarten dahingehend zu überprüfen, ob ihr Bestand gesichert und erhalten werden kann. So kann dann die Frage beantwortet werden, ob es gelungen ist, das Aussterben von Pflanzenarten in Hessen zu stoppen oder lediglich zu verlangsamen.
Im Rahmen des von der KfW Stiftung geförderten Artenschutzprojektes „Erhaltungskulturen von bedrohten Pflanzen in Hessen“ wurden in den Jahren 2014–2018 von 15 gefährdeten Pflanzenarten in verschiedenen Regionen Hessens Samen gesammelt und im Botanischen Garten der Stadt Frankfurt am Main vermehrt. In Zusammenarbeit mit Naturschutzbehörden, Forstämtern und Naturschutzverbänden wurden dokumentierte Wiederansiedlungsmaßnahmen oder Populationsstärkungen durchgeführt. Überzähliges Saatgut wurde im Botanischen Garten eingefroren und kann für zukünftige Artenschutzprojekte verwendet werden. Bei den 15 gefährdeten Arten handelt es sich um Allium strictum, Festuca albensis, Fumana procumbens, Iris spuria, Jurinea cyanoides, Mibora minima, Moenchia erecta, Nigella arvensis, Poa badensis, Scleranthus verticillatus, Sedum villosum, Spergula pentandra, Ventenata dubia, Veronica acinifolia und Vicia orobus. Alle diese Arten sind als Verantwortungsarten Bestandteil der hessischen Biodiversitätsstrategie. Im Jahr 2021, also drei Jahre nach dem Ende des Projektes, ergab eine Erfolgskontrolle folgendes Ergebnis: Von insgesamt 50 Wiederansiedlungsversuchen an 34 Orten sind immerhin 25 (50 %) erfolgreich. Weitere 5 (10 %) sind möglicherweise ebenfalls gelungen, jedoch sind die neu begründeten Populationen sehr klein. Eindeutig misslungen sind 20 (40 %). Die Gründe für das Misslingen sind meist klar erkennbar und werden thematisiert: Manchmal war der Zielort ungünstig gewählt, oder die verwendete Ansiedlungsmethode erwies sich als ungeeignet. Das Projekt konnte dazu beitragen, unser Wissen über Ökologie und Verbreitung sowie Gefährdung und Schutzbedarf dieser Verantwortungsarten teils erheblich zu vermehren. Damit leistet es auch einen Beitrag zum Schutz der bereits bestehenden Altpopulationen.
In diesem Artikel und weiteren geplanten Folgen werden Ergänzungen, Nachträge, Erläuterungen und Korrekturen sowohl zum von der Taunusflora (Wittig & al. 2022) erfassten Gebiet (Vortaunus, Hoher Taunus, kammnaher Hintertaunus) als auch zum bisher nicht bearbeiteten kammfernen Bereich des Hintertaunus publiziert. Bei den bisherigen Ergänzungen und Nachträgen handelt es sich um die Ergebnisse der Nachbestimmung eines Belegs (Allium christophii), den Fund einer für das Gebiet bisher nicht genannten Art (Hylotelephium vulgare) sowie um Hinweise auf ältere Funde (Bolboschoenus maritimus, Polystichum lonchitis) und einen neueren Fund (Luronium natans). Weiterhin werden die wichtigsten Ergebnisse der Begehungen sechs kammferner Rasterfelder präsentiert (Rote-Liste- und sonstige seltene Arten). Als selten werden diejenigen Arten angesehen, die im bisherigen Kartierungsgebiet in maximal 5 % (= 26) der insgesamt 523 Rasterfelder gefunden wurden. Außerdem werden in der Taunusflora enthaltene Fehler korrigiert.
Vergesellschaftung von Salzpflanzen an Straßenrändern unter besonderer Berücksichtigung des Taunus
(2023)
Im Taunus wurden an Straßen bisher fünf Arten festgestellt, die allgemein als Charakterarten der mitteleuropäischen Salzvegetation gelten und daher als Salzpflanzen im engeren Sinne bezeichnet werden können: Cochlearia danica, Plantago coronopus, Puccinellia distans, Spergularia marina und Trifolium fragiferum. Mit Ausnahme der Vorkommen von Trifolium fragiferum handelt es sich dabei oft um nur wenige weitere Arten enthaltende Dominanzbestände, wobei Trittpflanzen am häufigsten vertreten sind, so dass Straßenrandvegetation mit Puccinellia distans in der vorliegenden Literatur allgemein den Trittpflanzengesellschaften zugeordnet wurde (Plantaginetea majoris beziehungsweise Polygono-Poetea annuae). Entsprechendes gilt auch für viele Vorkommen von Plantago coronopus. Wie die vorliegende Arbeit zeigt, können aber einige der aus dem Taunus vorliegenden Aufnahmen mit Plantago coronopus zu den Salzwiesen im weiteren Sinne gestellt werden (Juncetea maritimi). Entsprechendes gilt für die hier präsentierte Vegetationsaufnahme eines Cochlearia-danica-Bestandes. Trifolium fragiferum wurde dagegen in einer als Flutrasen (Molinio-Arrhenatheretea, Agrostietalia stoloniferae) zu bezeichnenden Pflanzengesellschaft angetroffen.
Unsere bisherige Kenntnis zur Situation von Crepis praemorsa (Abbiss-Pippau) war ungenügend und wurde im Rahmen eines Kooperationsprojektes mit dem Hessischen Landesamt für Naturschutz, Umwelt und Geologie (HLNUG) erheblich verbessert. Die Untersuchungen zeigen, dass es in Hessen offenbar nur noch acht Vorkommen dieser Art gibt: Drei sehr kleine Reliktpopulationen an der Bergstraße, eine im nordhessischen Bergland und vier in der Rhön, davon zwei sehr kleine. Keine der Populationen kann als groß bezeichnet werden, die Anzahl der Individuen liegt zwischen wenigen Exemplaren bis zum niedrigen dreistelligen Bereich. Lediglich eine Population erscheint aktuell ungefährdet. Fehlende Nutzung oder Pflege und in der Folge Verbrachung und Verbuschung sowie Lichtmangel durch Beschattung sind maßgebliche Gefährdungen. Ohne aktive Hilfsmaßnahmen werden vier dieser acht Populationen in naher Zukunft erlöschen.
Buchbesprechungen
(2022)
Es werden folgende Publikationen rezensiert: Jansen W. & T. Gregor 2021: Rubi hassici – die Brombeeren Hessens; Schmidt M. & P. Meyer (Gesamtredaktion) 2019: Hessische Naturwaldreservate im Portrait. Waldgebiet östlich Oppershofen; Schmidt M. & P. Meyer (Gesamtredaktion) 2020: Hessische Naturwaldreservate im Portrait. Schloßberg; Schmidt M., J. Evers, T. Hövelmann, K. Lorenz, U. Paar, R. Starke & P. Meyer 2021: Hessische Naturwaldreservate im Portrait. Niestehänge; Stützel T. 2021: Botanische Bestimmungsübungen. 4. Auflage; Ssymank A., G. Ellwanger, M. Ersfeld, J. Ferner, S. Lehrke, C. Müller, U. Raths, M. Röhling & M. Vischer-Leopold 2021: Das europäische Schutzgebietssystem Natura 2000. BfN-Handbuch zur Umsetzung der Fauna-Flora-Habitat-Richtlinie (92/43/EWG) und der Vogelschutzrichtlinie (2009/147/EG). Zweite, erweiterte und geänderte Auflage. Band 2.1: Lebensraumtypen der Meere und Küsten, der Binnengewässer sowie der Heiden und Gebüsche; Tietze A., C. Hepting, V. Hollmann, L. Jeske, I. Leyer, S. Liepelt, A. Peters & J. Weise 2020: Wilde Arnika – Ein Leitfaden für die Praxis; Verband Botanischer Gärten (2021): Neue Wilde – Globalisierung in der Pflanzenwelt.
Die Fundmeldungen in Band 34 von Botanik und Naturschutz in Hessen stammen von: Dirk Bönsel, Martin De Jong, Klaus Dühr, Uta Engel, Benjamin Feller, Christian Feuring, Thomas Gregor, Arthur Händler, Karsten Horn, Diemut Klärner, Julia Kruse, Eric Martiné, Hasko Friedrich Nesemann, Kai Uwe Nierbauer, Uwe Raabe, Susanne Raehse, Felix Reischmann, Bernd Sauerwein, Petra Schmidt, Fabian Schrauth, Christof Nikolaus Schröder, Helmut Siebert, Michael Thieme, Otto Wacker und Rüdiger Wittig.
Linaria arvensis steht in Hessen und bundesweit kurz vor dem Aussterben. Im Rahmen des Kooperationsvertrages mit dem Land Hessen wurde Linaria arvensis in Hessen untersucht. Insgesamt gab es zwei Positivnachweise am Auleberg bei Schlierbach und in einem Acker am Waldrand westlich Frankenbach. Die Populationen sind sehr klein und könnten in den nächsten Jahren verschwunden sein. Vor allem in Schlierbach steht die Population kurz vor dem Erlöschen. Alle weiteren untersuchten ehemaligen Fundstellen erbrachten keine neuen Nachweise.
2020 und 2021 wurden Kalksümpfe im Main-Kinzig-Kreis untersucht, für die meisten Gebiete liegen Daten aus der zweiten Hälfte der 1980er Jahre vor. Ein Großteil der Gebiete konnte durch Pflege erhalten werden. Das wichtigste Gebiet, die Lietebachquelle bei Ahlersbach, ist allerdings durch mangelnde Pflege deutlich beeinträchtigt. Ein isoliert liegendes Gebiet bei Meerholz wurde durch die Anlage von Tümpeln völlig zerstört. Insbesondere konkurrenzschwache, kleinwüchsige Arten wie Carex pulicaris sind stark rückläufig.
Die basenreichen, offenen Sand-Lebensräume des hessischen Oberrheingebietes sind bekannt für ihre mittlerweile hochgradig gefährdeten Pflanzen- und Tierarten sowie Vegetationstypen. Inzwischen kommen nur noch Reste der früher weitverbreiteten Lebensräume vor, und daher gibt es Projekte im Naturschutz, Trittsteine und Korridore zu restituieren, um die fragmentierten Lebensräume wieder zu verbinden. Seit dem Jahre 1998 entwickelten wir Methoden für Restitutionsprojekte und führten ein wissenschaftliches Monitoring in den Sand-Lebensräumen durch (zusammen mit dem Landkreis Darmstadt-Dieburg, der Stadt Darmstadt und einem Landschaftspflegehof). Dafür wurden biotische und teilweise zusätzlich abiotische Verbesserungen der Flächen kombiniert mit Beweidung. Erstmals können wir nun mit Hilfe von jährlichen pflanzensoziologischen Aufnahmen und ihrer Analyse die 16jährige Vegetationsentwicklung eines ehemaligen Sandackers als Modell für eine Restitution ohne abiotische Maßnahmen aufzeigen. Ergänzend vergleichen wir diese Aufnahmen auch mit solchen der nahegelegenen Leitbildfläche Griesheimer Düne. Die Restitutionsfläche wurde mit Pflanzenmaterial (Rechgut) von Leitbildflächen inokuliert und danach kontinuierlich mit Schafen und Eseln beweidet. Aus Sicht des Naturschutzes war die Entwicklung erstaunlich gut, obwohl die Phosphat-Konzentration im Oberboden trotz Reduktion im 16. Jahr immer noch beträchtlich war. Mittlerweile ist die Anzahl und die Deckung an Zielarten hoch, im Falle von Arten der Koelerio-Corynephoretea sogar höher als in der benachbarten Leitbildfläche. Auch kommt eine Vielzahl an Rote-Liste-Arten vor. Aber es gibt auch ein ruderales Potenzial vor allem mit den Schlüsselarten Calamagrostis epigejos und Cynodon dactylon. Das Beweidungsmanagement muss in der bisherigen Intensität fortgeführt werden, um die Entwicklung insbesondere dieser Arten zu kontrollieren.
Im Rahmen des Kooperationsvertrages mit dem Land Hessen wurde Teucrium scordium, der Knoblauch-Gamander, in Hessen 2021 nachgesucht. Das Ergebnis zeigt, dass Teucrium scordium in Hessen stark gefährdet ist. An den neun überprüften Stellen gab es vier Positivnachweise. Die größte Population befindet sich im Natura-2000-Gebiet „Untere Gersprenz“ bei Hergershausen. Weitere Positivnachweise gelangen in einem Graben am Reichelsheimer Flugplatz, in einer Nasswiese bei Nauheim sowie in einer Sandgrube bei Dudenhofen. Aktuell liegt nur in der Sandgrube eine Gefährdung durch Sukzession vor. Die übrigen Populationen scheinen stabil zu sein.